+1 for the staintune system. Great local product! It did seem to let it spin up quicker after fitting. But i felt that the bike wasn't running as smooth. So did the power commander thing and this fixed it up with better fuel consumption. If it wasnt for the P/commander i'd prefer the stock setup. Dynotuned the setup and made as good if not better power with the restricter in compared to it out. 98.11hp & 78.38ft-lbs without restricter. 97.62hp & 82.73ft/lbs with restricter. The latter was 5°c cooler and 20% difference in humidity to be fair, so no restricter might have a small edge. I like the restricter out but when 2up cant get starcomm to stop picking up pipe noise from pillions hat. Also 2 up we get exhaust gasses hanging around because of my huge aeroflow windscreen. Restricter mostly used now.